Partitioning of Fatty Acids in Oil/Water Systems Analyzed by HPLC

Surfactant/oil/water systems in which the surface-active substance is a mixture of an undissociated fatty acid (FA) and its sodium salt soap, exhibit the typical phase behavior and the general emulsion phenomenology produced by a formulation scan. The phase behavior transition is induced by changing the FA concentration in the system at a fixed alkaline (NaOH) content in water, which results in a variable lipophilic acid/hydrophilic salt ratio. The partitioning is reported for different FA types (octanoic to myristic) and alcohol co-surfactants between excess oil and water phases of Winsor three-phase optimum formulation system. The concentrations are determined by using a method reported in a previous work to quantify the total acid fraction in each phase.

ROCK inhibition prevents tau hyperphosphorylation and p25/CDK5 increase after global cerebral ischemia.

Rho-kinase (ROCK) is a downstream effector of RhoA, which has been associated with growth cone collapse and retraction in neurons. ROCK inhibition has been shown to protect against ischemic damage, thereby improving short-term collateral flow, inhibiting platelet aggregation, leukocyte adhesion, and preventing neuronal death. However, little is known about the long-term effects of ROCK inhibition on behavior and neuroprotection. The consequence of ROCK inhibition on ischemic rats' learning and spatial memory after 30 days of intracerebroventricular treatment was evaluated. It was found that Y27632 (ROCK inhibitor) reduced neurodegenerative markers, such as Fluoro-Jade, PHF (paired helicoidal filaments) immunoreactivity, and p25 protein levels, in the hippocampus of ischemic animals and improved learning and spatial memory tasks. However, Y27632 alone impaired sham animals' long-term memory. These findings demonstrated the beneficial impact of ROCK inhibition on tauopathy and altered p25 protein levels following global cerebral ischemia. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Modified solvent accessibility free energy prediction analysis of cyclic urea inhibitors binding to the HIV-1 protease

One of the most successful drug targets against AIDS in thelast decade has been the HIV-1 protease (HIV-1 PR), an enzymethat processes the polyprotein gene products into active replicativeviral proteins. In our quest for a wide-ranging, binding freeenergy function we have extended the solvent accessibility freeenergy predictor (SAFE_p) method, recently developed for peptidicHIV-1 PR inhibitors, to the study of the binding of cyclic urea(CU) HIV-1 PR inhibitors. Our results show that there is a needfor a specific term depicting polar contacts to be added tothe original SAFE_p analytical expression, an outcome not seenin our studies of HIV-1 PR peptidic inhibitors. Nevertheless,despite the higher profile of the electrostatic interactionsin the binding of the CU inhibitors, our analysis indicatesthat CU inhibitor binding is still driven by the hydrophobicentropic contribution, as much as for the peptidic inhibitors.     

Using the node's experience from previous transmissions to improve the communication in an indoor localization system

Although originally the wireless sensor networks (WSN) were designed for transmitting environmental parameters with a low data rate, there is a growing need to use these networks for applications that require high throughput, such as real time localization systems (RTLS).     

Simple and efficient inductive telemetry system with data and power transmission

This paper presents an inductive telemetry system useful for isolated applications that have to be powered and/or controlled from outside. The transmitter is based on a Class-E amplifier with ASK modulation generated with a resonant modulation to obtain the different levels to transmit. In the receiver two possible configurations, parallel and serial, are studied and the serial configuration is proposed to reduce the effect of the rectifier and the filter over the received signal. Also an ASK demodulator is fabricated in an ASIC. All the system (transmitter-receiver) has been tested and a 60% of efficiency in power transmission is obtained at a distance of 10 mm. For the data link a bit rate 1 Mbps with a carrier of 8 MHz at a distance of 20 mm has been obtained.     

Spectroscopy of atomic chains with tunneling microscopy

Recently, it has been possible to create metallic chains down to seven-atom long. This has two implications. Experimentally it is necessary to have algorithms that allow converting measured data into microscopic information as, for example, processing a current-voltage curve to obtain electronic density of states (DOS). From a theoretical standpoint, we have a new framework to test extant theories and to further develop them. With this in mind, we present a new theoretical solution to the problem of mapping scanning tunneling microscopy current-voltage curves into DOS-energy curves. Our model is based on a self-consistent solution to the quantum problem of electrons in the presence of an array of attractive centers. The problem, being simpler than its three-dimensional counterparts is solved exactly for DOS and for the current-voltage curves. The main results are that the current-voltage peaks at the position of the energies of the electron in the chain and, when an impurity is present in the chain, its chemical information can be extracted from the value of analytical curves.